The Biobío River springs from Icalma and Galletue lakes in the Andes, flows through steep and narrow gorges and forests of araucaria pine, passes through agricultural lands and cities, until it reaches the Pacific Ocean, 380 km from its source. Its watershed has a surface area of 24,260 square kilometers and is 380 km long. Over one million people use the resources of the Biobío for drinking and irrigation water, recreation, and fisheries.

The upper Biobío, the site of the proposed dam, is home to Chile’s most traditional indigenous people, the Pehuenche. A significant number of indigenous families refuse to leave their traditional homelands in the Upper Biobío. This will likely force a court battle between Chile’s Indigenous Law (designed to protect the lands of Chile’s indigenous population) and Chile’s Electric Law (passed during Pinochet’s regime, the law gives carte blanche to any project that provides energy for the country).